The final paragraph mentions police attention to sites of former murders. Modern profiling, unknown to police of 1888, indicates serial killers do their first murders close to their homes. Perhaps unwittingly the police presence was very close to home for the murderer. Maybe this is why there were no murders in October. If the killer did live close to the crime scenes he may well have seen, noticed, even felt the police presence. Even if he thought he could get away with a murder a few blocks from home, perhaps he feared trying to get return through the police presence.

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The wickedness of the world is the dream of the plague.~~Voynich Manuscript